When you have the ball, make sure one of your teammates are under/near the basket. Then hit L2+X. That should make the person with the ball, lob the ball up for an alley oop.
Defeating Michael Jordan
Although the following trick can be done with any point total to win, 11 is probably the best. Choose Jeff Hornacek to play against Michael Jordan. After getting the ball, just shoot three-pointers. Michael will not guard you until your start to make a lot of shots or get a big lead. When he does start to guard, back up a few feet from the three point line and shoot the ball. He will not guard and you can still make the basket. Note: Make sure to release ball at the top of your jump. Jeff Hornacek will not always make it, so only shoot the three-pointer on every other shot. He should make about 90% if he shoots every other shot. Try to drive on every possession when you do not shoot a three.
Easier Three-Pointers
When you have the ball, get into three point territory. Quickly tap the circle button. That should make you fake a shot, and your opponent should jump in the air. When he is at the top of his jump, shoot the ball. Your opponent won't have enough time to recover and will not be able to block your shot. This will give you a better chance of making the three pointer. (I've noticed that if a defender isn't jumping in front of you during a shot, the ball tends to have a better chance of going in, rather than him destracting your player.)
Unlock Isaiah Thomas
Get fifteen steals in a game in superstar mode to unlock him on the roster
Unlock Michael Jordan
Defeat Michael Jordan one on one in superstar mode to unlock him on the roster.
Alley Oop...